Alexis Colvin, MD, Associate Professor of Orthopaedics at the Icahn School of Medicine at Mount Sinai said the sudden pileup of ligament-replacement candidates in baseball shouldn't be thought of as an irreversible trend. Like other medical issues, the causes can be identified through more research, and greater action can be taken at the youth-sport level. "With players, coaches and parents,'' said Dr. Colvin, "you're going to have to have more of a societal shift.''